The effects of kefir consumption on human health: a systematic review of randomized controlled trials.

CONTEXT: Kefir, a traditional, fermented-milk beverage, has increasingly been promoted for various health benefits. The evidence from systematic reviews, however, is limited. OBJECTIVE: Evidence from randomized controlled trials testing oral consumption of fermented-milk kefir on any outcome of human health or disease. DATA SOURCES: A systematic search of 4 electronic databases (PubMed, Scopus, Allied and Complementary Medicine Database, and Cochrane Trials) from inception to July 31, 2021, was conducted. DATA EXTRACTION: Data extraction and risk-of-bias assessments were conducted by 2 reviewers independently. DATA ANALYSIS: A total of 18 publications reporting the results of 16 studies were included. Per the narrative analysis, fermented-milk kefir may have potential as a complementary therapy in reducing oral Streptococcus mutans, thereby reducing dental caries risk, and in Helicobacter pylori eradication therapy. Kefir may further aid treatment of adult dyslipidemia and hypertension, although evidence was very limited. Safety was only assessed in 5 of the 18 included publications, and 12 of the studies had an overall high risk for bias. CONCLUSION: Kefir is a dairy product with a unique microbiological profile that appears to be a safe for generally healthy populations to consume. However, efficacy and safety data from high-quality human trials are essential before any recommendations may be made for conditions of the oral and gastric microbiota and metabolic health. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42020211494.

Clinical assessment and cytokines level in constipation-predominant irritable bowel syndrome participants treated with Lactobacillus-containing cultured milk drink.

BACKGROUND: Gut dysbiosis is linked with the pathophysiology of irritable bowel syndrome (IBS). Manipulation of intestinal microbiota using cultured milk drinks may stimulate the immune system, hence providing beneficial support in IBS treatment. This study aimed to investigate the effects of cultured milk drink on clinical symptoms, intestinal transit time (ITT), fecal pH and cytokines in constipation-predominant IBS (IBS-C) as compared to non-IBS participants. METHODS: Each recruited participant was given three bottles of 125 ml cultured milk drink containing 109 cfu Lactobacillus acidophilus LA-5 and Lactobacillus paracasei L. CASEI-01 consumed daily for 30 days. At pre- and post-30-day consumption, fecal pH, ITT, clinical symptoms, IL-6, IL-8 and TNF-α levels were assessed. Seventy-seven IBS-C and 88 non-IBS were enrolled. RESULTS: Post-consumption, 97.4% of IBS-C experienced improvements in constipation-related symptoms supported by the significant reduction of ITT and decreased fecal pH (p<0.05). All pro-inflammatory cytokines were significantly lower in post as compared to pre-consumption of cultured milk drinks in IBS-C (p<0.05). There was significant reduction in the IL-8 and TNF-α levels in post- as compared to pre-consumption for the non-IBS (p<0.05). CONCLUSION: Cultured milk drink taken daily improved clinical symptoms and reduced cytokines, hence should be considered as an adjunctive treatment in IBS-C individuals.

A influência de bebida láctea com cultura probiótica (Bifidobacterium animalis) no tratamento dos sintomas de constipação / Influence of drinking a probiotic fermented milk beverage containing bifidobacterium animalis on the symptoms of constipation

ABSTRACT BACKGROUND Constipation is a chronic problem in many patients all over the world. OBJECTIVE - To evaluate the effect of consumption of a probiotic fermented milk beverage containing Bifidobacterium animalis on the symptoms of constipation. METHODS - This randomized, double-blind controlled trial included 49 female patients aged 20 to 50 years and diagnosed with constipation according to the ROME III criteria (Diagnostic Criteria for Functional Gastrointestinal Disorders) and the Bristol Stool Form Scale. The patients were randomized into two groups: the intervention group received the probiotic fermented milk beverage and the control group received non-probiotic milk. Participants were instructed to ingest 150 mL of the beverages during 60 days. At the end of this period, patients were assessed again by the ROME III criteria and Bristol scale. The Wilcoxon test was used to evaluate pre and post-intervention results of the ROME III criteria and Bristol scale. The statistical significance level was considered as 5% ( P ≤0.05). RESULTS - The intervention group showed improvement in the following criteria: straining during a bowel movement ( P <0.001), feeling of incomplete evacuation ( P <0.001) and difficulty in passing stool ( P <0.014), in addition to Bristol scale results ( P <0.001). In the control group, improvements were observed in the following criteria: straining during a bowel movement ( P <0.001), feeling of incomplete evacuation ( P <0.001) and difficulty in passing stool ( P <0.025), in addition to Bristol scale results ( P <0.001). No statistically significant post-intervention differences were observed between the two groups for the Rome III criteria and Bristol scale. CONCLUSION - The results show that the consumption of milk resulted in the improvement of constipation symptoms, regardless of the probiotic culture.

RESUMO CONTEXTO - Constipação é um sintoma crônico que acomete grande parte da população mundial. OBJETIVO - Avaliar o efeito do consumo de bebida láctea com cultura probiótica ( Bifidobacterium animalis ) nos sintomas de constipação intestinal. MÉTODOS - Ensaio clínico randomizado, duplo cego e controlado. A amostra foi de 49 pacientes, do gênero feminino, com idade entre 20 a 50 anos e com diagnóstico de constipação intestinal conforme os critérios de ROMA III ( Diagnostic Criteria for Functional Gastrointestinal Disorders ) e escala de Bristol. As pacientes foram divididas em dois grupos através de randomização, o grupo intervenção recebeu bebida láctea com cultura probiótica e o grupo controle recebeu bebida láctea. Estas foram orientadas a consumir 150 mL diariamente durante 60 dias. Ao final deste período, aplicaram-se novamente os critérios de ROMA III e escala de Bristol. Para avaliação dos critérios de ROMA III e escala de Bristol pré e pós-intervenção, o teste de Wilcoxon foi aplicado. O nível de significância estatística considerado foi de 5% ( P ≤0,05). RESULTADOS - No grupo intervenção houve melhora nos seguintes critérios: esforço para evacuar ( P <0,001), sensação de evacuação incompleta ( P <0,001) e dificuldade na passagem das fezes ( P =0,014), além da escala de Bristol ( P =<0,001). No grupo controle houve melhora nos seguintes critérios: esforço para evacuar ( P <0,001), sensação de evacuação incompleta ( P <0,001) e dificuldade na passagem das fezes ( P =0,025), além da escala de Bristol ( P =<0,001). Verificou-se que os critérios de Roma III e escala de Bristol não houve diferenças estatisticamente significativas entre os grupos pós-intervenção. CONCLUSÃO - Concluiu-se que o consumo de bebida láctea auxiliou na melhora dos sintomas de constipação intestinal, independentemente da cultura probiótica.

The Neuroprotective Effect of Kefir on Spinal Cord Ischemia/Reperfusion Injury in Rats.

OBJECTIVE: The main causes of spinal cord ischemia are a variety of vascular pathologies causing acute arterial occlusions. We investigated neuroprotective effects of kefir on spinal cord ischemia injury in rats. METHODS: Rats were divided into three groups : 1) sham operated control rats; 2) spinal cord ischemia group fed on a standard diet without kefir pretreatment; and 3) spinal cord ischemia group fed on a standard diet plus kefir. Spinal cord ischemia was performed by the infrarenal aorta cross-clamping model. The spinal cord was removed after the procedure. The biochemical and histopathological changes were observed within the samples. Functional assessment was performed for neurological deficit scores. RESULTS: The kefir group was compared with the ischemia group, a significant decrease in malondialdehyde levels was observed (p<0.05). Catalase and superoxide dismutase levels of the kefir group were significantly higher than ischemia group (p<0.05). In histopathological samples, the kefir group is compared with ischemia group, there was a significant decrease in numbers of dead and degenerated neurons (p<0.05). In immunohistochemical staining, hipoxia-inducible factor-1α and caspase 3 immunopositive neurons were significantly decreased in kefir group compared with ischemia group (p<0.05). The neurological deficit scores of kefir group were significantly higher than ischemia group at 24 h (p<0.05). CONCLUSION: Our study revealed that kefir pretreatment in spinal cord ischemia/reperfusion reduced oxidative stress and neuronal degeneration as a neuroprotective agent. Ultrastructural studies are required in order for kefir to be developed as a promising therapeutic agent to be utilized for human spinal cord ischemia in the future.

Yogurt for treating antibiotic-associated diarrhea: Systematic review and meta-analysis.

OBJECTIVE: Antibiotic-associated diarrhea (AAD) is a common complication in individuals treated with antibiotics. The aim of this review was to systematically evaluate the efficacy of yogurt consumption for the prevention of AAD. METHODS: In this systematic review, a number of databases including MEDLINE, EMBASE, and the Cochrane Library, with no language restrictions, were searched up to September 2014 for randomized controlled trials (RCTs) evaluating the effect of yogurt consumption in adults and children who were receiving antibiotics. The risk for bias was assessed using the Cochrane risk of bias tool. RESULTS: Two RCTs, both low in methodological quality, were included. Compared with no intervention, yogurt consumption reduced the risk for diarrhea in the fixed effect model (two RCTs, n = 314, relative risk [RR], 0.56; 95% confidence interval [CI], 0.31-1.00). Significant heterogeneity between the trials was detected (I(2) = 67%). The significant reduction in the risk for diarrhea was lost in the random effects model (RR, 0.45; 95% CI, 0.11-1.75). CONCLUSIONS: Given the simple nature of the intervention, the scarcity of data is noteworthy. No consistent effect of yogurt consumption for preventing AAD was shown. However, the data are limited and the included trials had methodological limitations. Results from large, rigorously designed RCTs are needed to assess the effect of yogurt consumption on AAD prevention.

Yogurt for treating acute gastroenteritis in children: Systematic review and meta-analysis.

BACKGROUND: In May 2014, the updated guidelines for the management of acute gastroenteritis (AGE) were published. The use of yogurt in the nutritional management of AGE was not addressed, although it is frequently used in many countries for this purpose. We aimed to systematically evaluate the efficacy of yogurt consumption for the management of AGE in children. DESIGN: In this systematic review, a number of databases, including MEDLINE, EMBASE, and the Cochrane Library, with no language restrictions, were searched up to July 2014 for randomized controlled trials (RCTs) evaluating the effect of yogurt consumption in children with AGE. The risk of bias was assessed using the Cochrane risk of bias tool. RESULTS: Four RCTs (n = 448) that were generally low in methodological quality, all performed in hospital setting, were included. Compared with placebo/no intervention, yogurt consumption had no significant effect on stool volume. The data on the effect of yogurt consumption on the duration of diarrhea and stool frequency were not consistent. The chance of treatment success (or failure) was similar in both groups. Compared with placebo, the duration of hospitalization was shorter in children who received yogurt, but the difference was of a borderline significance. Total weight gain increased for those treated with yogurt. CONCLUSIONS: The consumption of yogurt had a positive effect on weight gain, but no consistent effect on AGE outcomes in hospitalized children. Given the limited data and the methodological limitations of the included trials, the evidence should be viewed with caution. The effect of yogurt consumption in the ambulatory setting is unknown.

The Neuroprotective Effect of Kefir on Spinal Cord Ischemia/Reperfusion Injury in Rats

OBJECTIVE: The main causes of spinal cord ischemia are a variety of vascular pathologies causing acute arterial occlusions. We investigated neuroprotective effects of kefir on spinal cord ischemia injury in rats. METHODS: Rats were divided into three groups : 1) sham operated control rats; 2) spinal cord ischemia group fed on a standard diet without kefir pretreatment; and 3) spinal cord ischemia group fed on a standard diet plus kefir. Spinal cord ischemia was performed by the infrarenal aorta cross-clamping model. The spinal cord was removed after the procedure. The biochemical and histopathological changes were observed within the samples. Functional assessment was performed for neurological deficit scores. RESULTS: The kefir group was compared with the ischemia group, a significant decrease in malondialdehyde levels was observed (p<0.05). Catalase and superoxide dismutase levels of the kefir group were significantly higher than ischemia group (p<0.05). In histopathological samples, the kefir group is compared with ischemia group, there was a significant decrease in numbers of dead and degenerated neurons (p<0.05). In immunohistochemical staining, hipoxia-inducible factor-1alpha and caspase 3 immunopositive neurons were significantly decreased in kefir group compared with ischemia group (p<0.05). The neurological deficit scores of kefir group were significantly higher than ischemia group at 24 h (p<0.05). CONCLUSION: Our study revealed that kefir pretreatment in spinal cord ischemia/reperfusion reduced oxidative stress and neuronal degeneration as a neuroprotective agent. Ultrastructural studies are required in order for kefir to be developed as a promising therapeutic agent to be utilized for human spinal cord ischemia in the future.